tf VOYAGE IN SEARCH 



tionate to the degree of heat that decompofes tbtf 

 mater. 



As this gas, the fpecific gravity of which was 

 rft afcertained by Pricltley, is much lighter 

 than the atmofpheric air, and as it has befides 

 little adherence to the water> it is eafy to fepa- 

 rate the former from the latter, and to red ore to 

 this beverage its primitive purity : for this it is 

 fufficient to agitate it for a quarter of an hour. 



We had on board a machine which perfectly 

 anfwercd this end: it was a large tub of the fize 

 of a double hectoliter : when it was three fourths 

 filled with water, there were turned round in 

 its middle, by means of a winch and a catch- 

 wheel, four large iron plates difpofed in the 

 form of a crofs ; the water then received a ftrong 

 agitation, which, by difengaging the inflam- 

 mable gas with which it was impregnated, re- 

 stored to it, at the fame time, the pure air of 

 which it had been partly deprived ; and, however 

 tainted it was before, it did not, in a very little 

 *hile, differ from the heft water. 



ThU procefs, which is very cafily executed, 

 < omplctcly rcfolvcs the numerous feries of quef- 

 rhkfa fomc natural philofophcrs have pro- 

 pofed to navigators, refpecting the means of ren- 

 dering frefh water drinkable when it becomes 



rid on board a fhip. 



It 



